Shear-knife



(NoModeL) 2 Sheets-Sheet 1.

- H. AIKEN.

SHEAR KNIFE.

No. 402.381. I Patented Apr. 30, 1889.

WITNESSES] 'INVENTOR.

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(No Model.) I v 2 SheetsSheet 2.

7 H. AIKEN.

SHEAR KNIFE.

.No. 402,381. Patented Apr. 30, 1889.

a WITNESSES. INVENTOR.

' knife is outwardly exposed UNITED ST TES PATENT OFFICE.

HENRY AIKEN, or HOMESTEAD, PENNSYLVANIA.

SHEAR-KNIFE.

SPECIFICATION forming part of Letters Patent No. 402,381, dated April 30, 1889.

Application filed December 11, 1888. Serial No. 293,270- (No model.)

To all whom it mar/concern:

Be it known that I, HENRY AIKEN, of Homestead, in the county of Allegheny and State of Pennsylvania, have invented a'new and useful Improvem ent in Shear-Knives, of which the following is a full, clear, and exact descrip tion, reference being had to the accompanying drawings, formingv part of this specification, in which- Figure 1 is a front elevation of my improved shear-knives secured to their holders. Fig. 2 is a side view thereof. Fig. 3 is a face view of the upper knife. Fig. a is a side view thereof. Fig. 5 is a face view, and Fig. 6 is a side View, of one of the sections of the lower knife.

Like symbols .of reference indicate like parts in each.

I shall first describe the construction of my improved shear-knives, and shallthen indicate their advantages and the manner of their use. a

In the drawings, Figs. 1, 2, 3, and 4, 2 represents the moving knife of shears for cutting angle-shaped iron, and 3 is the knife-head to which it is secured. The knife is made-equilateral, preferably quadrilateral, in outline with rounded corners, and is set vertically in an angular cavity in the face of the knifehead, as shown in Fig. 1, so that two edges and the back of the knife shall be braced and supported by the knife-head and that the outer angle and the adj acent' edges of the knife shall be free to act in the operation of shearing. The knife is held to the knifeholder by bolts 4, which pass through registering and symmetrically-placed bolt-holes in the knife and in the knife-holder, as shown in Fig. 2, the bolt-holes in the knife being preferably countersunk on both sides, so that a recess shall be afforded for the head of the bolt, whether one side or the other of the (See Figs. 2 and 4.)

The cutting-edge of the bed-knife 6 of the shears is the counterpart in shape of the moving knife, and is set in an angular recess in a knife-holder, 5, which is suitably bolted to the frame of the machine. The knife is made in two parts, a and b, which are or may be similar in shape, being formed with equal angles at the ends thereof, so that when placedtogether, as shown in Fig. 1, the parts shall present a cutting-edge of the desired form, and that when reversed and readjusted, as hereinafter described, they shall present an angular knife of the same shape.

The knives are used in the ordinary manner of shear-knives,the metal being placed on the knife 6 and being sheared off bythe descent of the moving knife, though, if desired, the knife 6 may be used as the moving knife and the knife 2 as the stationary knife, or both knives may be movable in shearing the piece.

If the cutting-edges of the knife 2 should become broken or so worn as to be unfit for use without repair or grinding, a new cuttingedge may be presented by removing the bolts 4, turning the knife one-quarterround in the recess of the knife-holder, and the bolts again tightened to hold the knife in place. The knife is thus capable of being turned and of presenting four cutting edges or angles without reversing the faces of the knife in the holder, and four additional cutting-edges may be presented by reversing the faces of the knife and turning the knife one-quarter round from time to time as new cutting-edges may be required, so that the knife possesses eight cutting edges or angles. The lower knife, 6, is constructed to serve a similar purpose, and its parts may be shifted in position four times as the cutting-edge in use becomes worn out,

so that all four cutting-edges must be worn may be reversed laterally to present similar .90

cutting-edgescfi, 011 the opposite side,as shown in Fig. 6. This reversal is facilitated by the double countersinking of the bolt-holes, as before explained. An additional adjustment of these knife-sections is possible when the cutting-edges at the angle of the knife become more worn than the upper extremities of the sections. knife-sections may be exchanged without reversing either of them, so as to bring the upper corners of the sections into the position of the meeting angle, and vice versa. In this In such case the positions of the way four additional changes in position are possible.

The advantages of my improvement will be appreciated by those skilled in the art. The length of time during which the knives may be used Without repair by simple changes in position is the cause of saving considerable time and labor in the operation of the shears, and prevents the frequent annoyance which is occasioned by the necessity for removing and smithing the knives heretofore in common use.

The nature and scope of my invention is stated in the following claims, each of which states an item of invention unlimited by the elements and limitations contained in the others.

Phe knife-sections (i may also be made of different shape from that which I h ave shown for example each maybe hexagonal in form.

I claim 1. An angled shearduiife made in separate interchangeable sections constituting the sides of the angle, substantially as and for the r purpose described.

2. An angled'shear-knife made in sections which constitute the sides of the angle, each section having its ends formed at equal angles, so that the knife may be shifted to present fresh cutting-edges, substantially as and for the purposes described.

recess for reception of the shear-knife, and an equiangular polygonal shear-knife secured therein having shearing edges which fit against the sides of said recess, in virtue of which any one of its salient ang es maybe presented in cutting, in combination with a bed-knife having an angular cutting-edge the counterpart of the salient angle of the first named shear-knife, substantially as and for the purposes described.

In testimony whereof I have hereunto set my hand this 8th day of December, A. D. 1888.

IIEHRY AIKEN.

"W itnesses:

W. B. CoRWIn, THOMAS \V. ZAKEWELL. 

